Heidenhain ND 750 User Manual

0 (0)

User’s Manual

Position Display Units for Milling Machines

9/ 2000

Position display (ND 710 only two axes)

• Select coordinate axes

(ND 710 only X and Y)

• Select axis-specific operating parameters

Status display:

SET = Datum setting REF = blinking:

Traverse the reference points. On continuously: Reference points have been traversed.

∆ = Distance-to-go display 1 2 Datum 1 or 2

Inch = Display in inches SCL = Scaling factor

->❘❘<- = Touching the edge / centerline R = Radius/diameter display

R+/– = Radius compensation

• Select datum 1 or 2

• Page backward in the list of special functions

• Page backward in the list of parameters

HEIDENHAIN

Numerical input

• Change the algebraic sign

• Call the last dialog

• In the parameter list: change parameters

• Confirm entry

• In the parameter list page forward

Call radius compensation of the current tool

• Select special functions

• In the list of special functions page forward

• Cancel entry

• Reset the operating mode

• Zero the selected axis

(if activated in P80)

• Select parameters CL plus two-digit number

This manual is for the ND display units with the following software numbers or higher:

Part I Operating Instructions

ND 710 for two axes 246 271-06 ND 750 for three axes 246 271-06

About this manual

This manual is divided into two parts:

Part I: Operating Instructions

• Fundamentals of positioning

• ND functions

Part II: Installation and Specifications

• Mounting the display unit on the machine

• Description of operating parameters

Fundamentals 4 Switch-On, Traversing the Reference Points 9 Datum Setting 10 Tool Compensation 19 Moving the Axes with Distance-To-Go 20 Bolt Hole Circles and Bolt Hole Circle Segments 22 Linear Hole Patterns 25 Working with a Scaling Factor 28 Error Messages 29

Part II

Installation and Specifications Page 31

Part I Operating Instructions

Fundamentals

You can skip this chapter if you are already familiar with coordinate systems, incremental and absolute dimensions, nominal positions, actual positions and distance-to-go.

Coordinate system

To describe the geometry of a workpiece, the

Fundamentals

system is used. The Cartesian coordinate system consists of three mutually perpendicular axes X, Y and Z. The point of intersection of these axes is called the datum or origin of the coordinate system.

Think of the axes as scales with divisions (usually in millimeters) which allow us to fix points in space referenced to the datum.

To determine positions on a workpiece, the coordinate system is “ laid” onto the workpiece.

The machine axes are parallel to the axes of the coordinate system. The Z axis is normally the tool axis.

Cartesian*

coordinate

–X

Graduation

Datum or origin

–Z

–Y

Named in honor of the French mathematician and philosopher René Descartes (1596 to 1650)

Datum setting

The workpiece drawing is used as the basis for machining the workpiece. To enable the dimensions in the drawing to be converted into traverse distances of machine axes X, Y and Z, each drawing dimension requires a datum or reference point on the workpiece (since a position can only be defined in relationship to another position).

The workpiece drawing always indicates one absolute datum (the datum for absolute dimensions). However, it may contain additional relative datums.

In the context of a numerical position display unit,

datum setting

means bringing the workpiece and the tool into a defined position in relation to each other and then setting the axis displays to the value which corresponds to that position. This establishes a fixed relationship between the actual positions of the axes and the displayed positions.

You can set 2 absolute datum points and store them in nonvolatile memory.

1225

750

320

Absolute datum

700

125

216,5

900

950

250

216,5 125

-125

-216,5

Relative datums

250

Fundamentals

-250

-125

-216,5

150 0

-150

300±0,1

325

450

Absolute workpiece positions

Each position on the workpiece is uniquely defined by its absolute coordinates.

Example Absolute coordinates of position 1:

Fundamentals

If you are working according to a workpiece drawing with absolute dimensions, then you are moving the tool to the coordinates.

Relative workpiece positions

A position can also be defined relative to the previous nominal position. The datum for the dimension is then located at the previous nominal position. Such coordinates are termed relative coordinates or chain dimensions. Incremental coordinates are indicated by a preceding I.

Example Relative coordinate of position 2 referenced to

If you are working according to a workpiece drawing with incremental dimensions, then you are moving the tool by the dimensions.

Sign for incremental dimensioning A relative dimension has a positive sign when the axis is moved

in the positive direction, and a negative sign when it is moved in the negative direction.

X = 10 mm Y = 5 mm Z = 0 mm

position 1:

IX = 10 mm IY = 10 mm

Nominal position, actual position and distance-to-go The position to which the tool is to move is called the nominal

position ( given moment is called the actual position (I). The distance from the nominal position to the actual position is called the distance-to-go (

Sign for distance-to-go

When you are using the distance-to-go display, the nominal position becomes the relative datum (display value 0). The distance-to-go is therefore negative when you move in the positive axis direction, and positive when you move in the negative axis direction.

). The position at which the tool is actually located at any

Fundamentals

Position encoders

The position encoders on the machine convert the movements of the machine axes into electrical signals. The ND display unit evaluates these signals, determines the actual position of the machine axes and displays the position as a numerical value.

Workpiece

If the power is interrupted, the relationship between the machine axis positions and the calculated actual positions is lost. The reference

Fundamentals

marks on the position encoders and the REF reference mark evaluation feature enable the ND to quickly re-establish this relationship again when the power is restored.

Reference marks

The scales of the position encoders contain one or more reference marks. When a reference mark is crossed over, a signal is generated which identifies that position as a reference point (scale datum = machine datum).

When this reference mark is crossed over, the ND's reference mark evaluation feature (REF) restores the relationship between axis slide positions and display values which you last defined by setting the datum. If the linear encoders have distance-coded reference marks, you only need to move the machine axes a maximum of 20 mm to do this.

Position encoder

Scale in Distance-coded linear encoder reference marks

Reference mark

Switch-On, Traversing the Reference Marks

0 è 1

ENT...CL

ENT

Crossing over the reference marks stores the last relationship between axis slide positions and display values for datum points 1 and 2 in nonvolatile memory.

Note that if you choose clearing the dialog ENT ... CL with the CL key), this relationship will be lost if the power is interrupted or when the unit is switched off.

If you wish to use multipoint axis error compensation you must traverse the reference marks (see “ Multipoint axis error compensation” )!

Turn on power (switch located on rear panel). REF and decimal points in status display blink.

Confirm reference traverse mode. REF remains on continuously. Decimal points blink.

Cross over the reference marks in all axes (in any sequence). Each axis display becomes active when its reference mark is crossed over.

not

to traverse the reference marks (by

Switch-On, Traversing the Reference Marks

Datum Setting

If you want to save the datum points in nonvolatile memory, you must first cross over the reference marks.

Only after crossing over the reference marks can you set new datums or activate existing ones.

In P70, you can select:

Datum Setting

• Two datum points: The selected datum is displayed via 1 or 2

• Nine datum points: The selected datum is displayed in the lowest axis via d1 to d9.

There are several ways to set datums: Touch the edge of the workpiece with the tool and then set

the desired datum. You can also touch two edges and set the centerline between them as a datum, or touch the inside of a circle and set the circle center as a datum (see examples). The tool data of the tool used for this are automatically considered (see “ Tool Compensation” ).

To call a datum point you have set, proceed as follows:

You have set two datum points in P70:

Select datum 1 or 2.

You have set nine datum points in P70:

Press the datum key (“ d” blinks).

ENT

Enter a datum number (1 to 9).

Probing a workpiece edge to find a datum

Datum setting with the tool

The ND display units support the following probing functions:

“ PROBE EDGE” Setting a workpiece edge as datum.

“ PROBE MIDPOINT” Setting a midpoint between two

workpiece edges as datum.

“ PROBE CIRCLE” Setting the center of a circle as datum.

The probing functions are accessible in the SPEC FCT mode of operation.

The functions “ PROBE EDGE” , “ PROBE MIDPOINT” and “ PROBE CIRCLE” are described on the following pages.

Example:

Working plane X / Y Tool axis Z Tool radius R = 5 mm Axis sequence X – Y – Z

for datum setting

R=5mm

Datum Setting

Probing a workpiece edge to find a datum

SPEC

FCT

Datum Setting

PROBING

ENT

PROBE EDGE

ENT

•

Select a datum number (see page 10).

Select the special functions.

Select “ probing function.”

Confirm selection.

Confirm “ Probe edge.”

Select the X axis (if not already selected). SET lights. The ❘<- status symbol starts to blink.

PROBE X (appears only briefly))

Touch workpiece edge 1 with the tool.

ENT

X position is captured. “ SET edge“ appears briefly. SET starts to blink. Retract tool from workpiece. The ❘<- status symbol lights.

•

ENT

•

Enter position value for the datum. Tool radius is automatically compensated.

Y position is captured. SET lights. The ❘<- status symbol starts to blink.

PROBE Y (appears only briefly)

Touch workpiece edge 2 with the tool.

•

ENT

Y position is captured. “ SET edge“ appears briefly. SET starts to blink.

ENT

Enter position value for the datum in the Z axis.

Retract tool from workpiece. The ❘<- status symbol lights.

ENT

Enter position value for the datum in the Y axis. Tool radius is automatically

SPEC

FCT

After setting the datum, exit the

probing funtions.

Datum Setting

compensated.

Select the Z axis. SET lights. The ❘<- status symbol starts to blink.

PROBE Z (appears only briefly)

Touch workpiece surface with the tool.

ENT

Z position is captured. “ SET edge“ appears briefly. SET starts to blink. Retract tool from workpiece. The ❘<- status symbol lights.

•

only with ND 750

Probing workpiece edges to find a midpoint datum

The edges to be probed run parallel to the Y axis.

Follow the procedure below for all midpoints between two edges:

Datum Setting

SPEC

FCT

Select a datum number (see page 10).

Select the special functions.

SPEC

FCT

PROBING

ENT

Select the probing function.

Confirm selection.

•

+ 31 hidden pages